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Possible impact damage?

Discussion in 'Props, Shafts & Seals' started by tirekicker11, Feb 16, 2011.

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  1. tirekicker11

    tirekicker11 Senior Member

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    Yesterday I was at a full keel, sloop rigged, very well build 51' yacht that had run aground recently. The boat had hit an underwater rock full on at a speed of 7 knots (is what the owners claim)
    Apart from some minor (!) damage to the keel and rudder I found some cracks in the GRP on the internal side of the hull.

    I also found 2 cracks in the 2mm GRP laminate on the 18mm plywood partial bulkhead that divides galley from settee.
    It is an L-shaped galley on starboard with the short end facing forward, I have access to the lower part of the partial bulkhead trough a cabinet.
    The cracks run on both (fwd and aft) sides of the bulkhead about 7 inches up from and parallel to the hull join, the cracks are almost the total with of the bulkhead (approx 25''). There is no movement in the bulkhead and I don't think that the plywood core has cracked although I couldn't verify this.

    As this is a very 'difficult-to-get-to' location I would like your opinions as to whether this is damage to the structure of the boat that needs to be repaired and whether this could be damage from the grounding inpact.

    Your input is appreciated
  2. Capt J

    Capt J Senior Member

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    Without seeing the extent of the damage or pictures it's hard to say whether they're superficial cracks or serious. I however would repair the bulkheads as they are structural support for the hull.

    I loaded a sailboat that the delivery captain had bounced the keel off of the bottom coming in St. Augustine inlet. It seriously cracked several interior bulkheads (completely through on both sides) that were structural support for both the hull sides and deck. It was verified that the damage was not there prior to this as a survey was done a week before when the owner bought the vessel. It's a shame as it was a beautiful j-class (I think) racing sailboat.
  3. Fishtigua

    Fishtigua Senior Member

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    J,

    J-Boats are fin keeled rather than full keeled and are lightly built for racing, yet are very strong. I've raced on quite a few over the years.

    We have a French built boat in the yard at the moment that has suffered similar damage. It is less than a year old but the damage is extensive. The center of the interior has been removed for access and the keel dropped.

    All the stringers running from the keel have had to be ground out and repaired, around the chainplate mounts repaired and the bulkhead bonding re-done. A big mess. The keel will need some major surgery too.

    On a full keel cruiser, everything is a little heavier laid-up and (I hope) much less damage should have taken place. A full survey is the only way to find the extent of any damage.
  4. Capt J

    Capt J Senior Member

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    It doesn't happen to be red in color and the name starts with "cha______" is it?
  5. tirekicker11

    tirekicker11 Senior Member

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    Thanks for your input.
    I still wonder why there is so little damage to the boat but there are these 2 cracks on each side of the bulkhead that feels totally rigid.
  6. Capt J

    Capt J Senior Member

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    Because the bulkhead sounds like it is a lot more rigid then the rest of the hull. The rest of the hull flexed, yet the bulkhead didn't and absorbed the impact and cracked.
  7. tirekicker11

    tirekicker11 Senior Member

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    Thanks Capt J